JPH09219335A - Chip electronic component and mounting structure of it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chip electronic component preventing tombstone phenomenon for reflow soldering of it to the circuit substrate using cream solder, even if the chip size is small, and having a high free degree about chip mounting direction. SOLUTION: A chip electronic component 11 consists of a chip body 13 with width W and thickness T in size where there is no substantial difference between W and T, and terminal electrodes 14 and 15 furnished on both ends in the longer direction of the chip 13. A circuit substrate 12 is furnished with electrical connection lands 16 and 17 which are to be soldered respectively to the terminal electrodes 14 and 15, and mechanically fixing two lands 18 and 19. Mechanically fixing metal planes 20 and 21 on the chip body 13 are arranged so that two mechanically fixing lands 18 and 19 can be soldered to the plane 20 and 21 regardless whether a plane LW or plane LT faces the circuit substrate 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip-shaped electronic component and its mounting structure, and more particularly to a chip-shaped electronic component mounted on a circuit board by soldering and a mounting structure by the soldering. .

[0002]

2. Description of the Related Art FIG. 7 shows a conventional chip-shaped electronic component 1 and its mounting structure which are of interest to the present invention. The chip-shaped electronic component 1 includes a chip-shaped component body 2 defined by a dimension in the lengthwise direction, a dimension in the width direction, and a dimension in the thickness direction, and two component bodies 2 formed at both ends of the component body 2 facing each other in the longitudinal direction. Terminal electrodes 3 and 4
And

On the other hand, on the circuit board 5 on which the chip-shaped electronic component 1 is mounted, two electrical connection lands 6 and 7 are formed corresponding to the two terminal electrodes 3 and 4, respectively. . When mounting the chip-shaped electronic component 1 on the circuit board 5, for example, after cream solder is applied to the electrical connection lands 6 and 7 by printing or the like,
With the terminal electrodes 3 and 4 of the chip-shaped electronic component 1 positioned on the lands 6 and 7 for electrical connection,
Cream solder is reflowed. As a result, the terminal electrode 3
And 4 are soldered to electrical connection lands 6 and 7 by solders 8 and 9, respectively.

[0004]

However, when soldering by the above-mentioned solder reflow is performed,
As shown by an imaginary line in FIG. 7, the chip-shaped electronic component 1
A so-called tombstone phenomenon may occur. The tombstone phenomenon is likely to occur when the terminal electrodes 3 and 4 have different wettability with respect to solder or a difference in soldering temperature. Regarding the difference in wettability with respect to solder, for example, a plating film of tin or the like is formed in order to give good solderability to the terminal electrodes 3 and 4, but such a difference in thickness of the plating film and the terminal electrode This is caused by the difference in the oxidation state of the surfaces of 3 and 4.

In particular, this tombstone phenomenon is likely to occur when a small chip-shaped electronic component having a lengthwise dimension of 1.0 mm, a widthwise dimension of 0.5 mm, and a thicknesswise dimension of 0.5 mm is mounted. In order to prevent this tombstone phenomenon, measures to extend the solder reflow time are also taken, but this is not preferable because it reduces the efficiency of the mounting process.

Some chip-shaped electronic components, such as the chip-shaped electronic components exemplifying the above-described dimensions, are selected so that the widthwise dimension and the thicknesswise dimension are equal to each other. As described above, in the case of an electronic component in which there is no substantial difference between the width-direction dimension and the thickness-direction dimension, two surfaces defined by the length-direction dimension and the width-direction dimension and the length-direction dimension and the thickness-direction dimension are defined. It is preferable that the device can be mounted regardless of which of the two surfaces defined by the dimensions is oriented toward the circuit board. In particular, in the case of ultra-small chip-shaped electronic components, the handling for aligning them in a certain direction is extremely complicated, so there are few restrictions on the directionality when mounting on a circuit board. This is noted as a more advantageous feature than in the case of relatively large chip-shaped electronic components.

SUMMARY OF THE INVENTION An object of the present invention is to provide a chip-shaped electronic component and its mounting structure which can prevent mounting defects such as the tombstone phenomenon from occurring easily. Another object of the present invention is to provide a chip-shaped electronic component with less restrictions on the directionality of mounting on a circuit board.

[0008]

According to the present invention, first, a chip shape defined by a lengthwise dimension, a widthwise dimension and a thicknesswise dimension, and a substantial difference between the widthwise dimension and the thicknesswise dimension is provided. 2 is formed on both ends of the component main body that does not have
In order to solve the above-mentioned technical problem, which is directed to a chip-shaped electronic component having two terminal electrodes,
It is characterized by having the following configuration.

That is, in the chip-shaped electronic component according to the present invention, the two terminal electrodes are soldered to each other.
A circuit in which two electrical connection lands and two mechanical fixing lands are arranged between these electrical connection lands in a direction orthogonal to the direction in which the two electrical connection lands face each other. It is intended to be mounted on a substrate. Then, this chip-shaped electronic component is oriented such that either one of the two surfaces defined by the lengthwise dimension and the widthwise dimension and the two surfaces defined by the lengthwise dimension and the thicknesswise dimension face the circuit board. However, it is characterized in that the mechanical fixing metal surface positioned so as to be soldered to the two mechanical fixing lands is formed on the component body.

The above-mentioned mechanical fixing metal surface may be formed so as to extend integrally from the terminal electrode or may be formed independently of the terminal electrode. Further, the present invention provides two electrical connection lands and two mechanical fixing lands that are arranged between the electrical connection lands in a direction orthogonal to a direction in which the two electrical connection lands face each other. It is also directed to a structure in which chip-shaped electronic components are mounted on a circuit board on which lands are formed.

In the mounting structure of the chip-shaped electronic component according to the present invention, the chip-shaped electronic component includes a chip-shaped component main body and two terminal electrodes formed at both ends of the component main body opposite to each other in the longitudinal direction. , A metal surface for mechanical fixation formed in the central portion of the component body in the longitudinal direction, and two terminal electrodes of the chip-shaped electronic component are respectively soldered to two electrical connection lands of the circuit board. And the metal surface for mechanical fixing is soldered to the mechanical fixing land.

[0012]

According to the chip-shaped electronic component and the mounting structure thereof according to the present invention, not only the terminal electrodes are soldered to the electrical connection lands, but also the mechanical fixing metal surfaces are mechanically fixing lands. Is also soldered. Since the latter soldering acts so as not to stand up the chip-shaped electronic component, it is possible to prevent a mounting defect such as a tombstone from occurring in the mounting process.

Further, according to the chip-shaped electronic component of the present invention, there is substantially no difference between the dimension in the width direction and the dimension in the thickness direction of the component body, and the circuit board has two electrical connection lands. While the mechanical fixing land is provided between the two, the chip-shaped electronic component is provided on the component body with two surfaces defined by the longitudinal dimension and the width dimension and the longitudinal dimension and the thickness dimension. Whichever of the two specified surfaces is facing the circuit board,
A mechanical fixing metal surface is formed so as to be soldered to the mechanical fixing land. Therefore, the chip-shaped electronic component can be mounted in any posture in the four directions.

Further, since the mechanical fixing land to which the mechanical fixing metal surface is soldered is provided in two parts, the mechanical fixing metal surface is formed so as to extend integrally from the terminal electrode. However, the problem of electrical short circuit is not encountered regardless of the attitude of the chip-shaped electronic component.

[0015]

1 is a perspective view showing a chip-shaped electronic component 11 and a circuit board 12 on which the chip-shaped electronic component 11 is mounted, separated from each other. FIG. 2 is a cross-sectional view showing a state in which the chip-shaped electronic component 11 shown in FIG. 1 is mounted on the circuit board 12. Further, FIG. 3 is a view corresponding to FIG. 1, and shows another mounting posture of the chip-shaped electronic component 11.

The chip-shaped electronic component 11 comprises a chip-shaped component body 13 defined by a lengthwise dimension L, a widthwise dimension W and a thicknesswise dimension T. There is no substantial difference between the widthwise dimension W and the thicknesswise dimension T of the component body 13. In addition, terminal electrodes 14 and 15 are formed at both ends of the component body 13 that face each other in the longitudinal direction.

On the other hand, on the circuit board 12, between the two electrical connection lands 16 and 17 to which the above-mentioned two terminal electrodes 14 and 15 are respectively soldered, and between these electrical connection lands 16 and 17. Two mechanical fixing lands 18 and 19 are formed, which are arranged in a direction orthogonal to the direction in which these electrical connection lands 16 and 17 oppose each other.

Further, the component body 1 of the chip-shaped electronic component 11
The mechanical fixing metal surfaces 20 and 21 are formed on the top surface of the component 3 at the center of the component body 13 in the longitudinal direction.
In this embodiment, the mechanical fixing metal surfaces 20 and 21 are formed so as to extend integrally from the terminal electrodes 14 and 15, respectively. As shown in FIGS. 1 and 2, even if the posture in which one of the two surfaces (LW surface) defined by the lengthwise dimension L and the widthwise dimension is directed toward the circuit board 12, as shown in FIG. As shown, even if one of the two surfaces (LT surfaces) defined by the lengthwise dimension L and the thicknesswise dimension T is oriented toward the circuit board 12, the mechanical fixing metal surfaces 20 and 21. Are located to be soldered to the two mechanical locking lands 18 and 19.

Such a chip-shaped electronic component 11 is shown in FIG.
And, as shown in FIG. 2, when the LW surface is mounted toward the circuit board 12, the two terminal electrodes 14 and 15 are respectively connected to the two electrical connection lands 16 and 17 and the solder 2.
2 and 23 are soldered together, and one mechanical fixing metal surface 20 has two mechanical fixing lands 1.
8 and 19 and solder 24. These solderings are simultaneously achieved by solder reflow using, for example, cream solder. In this solder reflow process, the solder 24 for soldering the mechanical fixing metal surface 20 and the mechanical fixing lands 18 and 19 acts so as not to stand the chip-shaped electronic component 11.

On the other hand, when the chip-shaped electronic component 11 is mounted with the LT surface facing the circuit board 12, as shown in FIG. 3, the two terminal electrodes 14 and 15 each have two electrical connection lands 16 respectively. And 17 are soldered together so that one mechanical fastening metal surface 20 is on one mechanical fastening land 18 and the other mechanical fastening metal surface 2 is on the other side.
1 is soldered to the other mechanical fixing land 19. At this time, it should be noted that since the mechanical fixing lands 18 and 19 are separated from each other, even if the mechanical fixing metal surfaces 20 and 21 extend integrally from the terminal electrodes 14 and 15, respectively. 14 and 15
Is not electrically short-circuited.

FIGS. 4, 5 and 6 respectively show chip-shaped electronic components 11a and 1a according to another embodiment of the present invention.
It is a perspective view which shows 1b and 11c. The component body 13 shown in these drawings has the same dimensional ratio as the component body 13 shown in FIG. The terminal electrodes 1 are respectively provided on both end portions of the component body 13 which face each other in the longitudinal direction.
4a and 15a, 14b and 15b, and 14
c and 15c are formed.

In the chip-shaped electronic component 11a shown in FIG. 4, a mechanical fixing metal surface 25 is formed in the central portion of the component body 13 in the longitudinal direction independently of the terminal electrodes 14a and 15a. The metal surface 25 for mechanical fixing is the component body 13
Is formed so as to surround the periphery of the. In the chip-shaped electronic component 11b shown in FIG. 5, the terminal electrodes 14b and 1
Independently of 5b, mechanical fixing metal surfaces 26 and 27 are formed in the central portion of the component body 13 in the longitudinal direction. The mechanical fixing metal surfaces 26 and 27 are formed so as to cross the surfaces of the component body 13 that face each other.

In the chip-shaped electronic component 11c shown in FIG. 6, a mechanical fixing metal surface 28 is provided in the central portion of the component body 13 in the longitudinal direction independently of the terminal electrodes 14c and 15c.
29, 30, 31, 32, 33, 34 and 35 are formed. The metal surfaces 28 to 35 for mechanical fixing are the component body 1
It is formed so that two pieces are distributed on each of the four surfaces of No. 3.

The chip-shaped electronic components 11a, 11b and 11c shown in FIGS. 4 to 6 are mounted on a circuit board similar to the circuit board 12 shown in FIG. At this time, the mechanical fixing metal surfaces 25, 26 and 27, and 28 to 35 shown in FIGS. 4 to 6, respectively, are the mechanical fixing metal surfaces 20 and 2 shown in FIG.
It performs substantially the same function as 1. That is, even if the LW surface of the component body 13 is oriented toward the circuit board 12,
Even if the LT surface is oriented toward the circuit board 12, the mechanical fixing metal surfaces 25, 26 and 27, and 28 to 3
5 are respectively positioned so as to be soldered to the two mechanical fixing lands 18 and 19.

Although other forms of the mechanical fixing metal surface have been described with reference to FIGS. 4 to 6, the present invention is not limited to these and can be changed to other forms. In addition, in FIG. 4 to FIG. 6, the chip-shaped electronic component 11
It is preferable that the mechanical fixing metal surfaces 25 to 35 formed on a, 11b and 11c are not connected to electrodes (not shown) inside the component body 13.

Further, regarding the mounting structure of the chip-shaped electronic component according to the present invention, if the component main body of the chip-shaped electronic component has no substantial difference between the widthwise dimension and the thicknesswise dimension. The present invention is not limited to this, and can be applied to those having a substantial difference between these dimensions.

[Brief description of drawings]

FIG. 1 is a perspective view showing a chip-shaped electronic component 11 and a circuit board 12 on which the chip-shaped electronic component 11 according to an embodiment of the present invention are separated from each other.

FIG. 2 is a cross-sectional view showing a mounting structure of the chip-shaped electronic component 11 shown in FIG. 1 on a circuit board 12.

FIG. 3 shows another mounting posture of the chip-shaped electronic component 11,
It is a figure equivalent to FIG.

FIG. 4 is a perspective view showing a chip-shaped electronic component 11a according to another embodiment of the present invention.

FIG. 5 is a perspective view showing a chip-shaped electronic component 11b according to still another embodiment of the present invention.

FIG. 6 is a perspective view showing a chip-shaped electronic component 11c according to still another embodiment of the present invention.

FIG. 7 is a sectional view showing a mounting structure of a conventional chip-shaped electronic component 1.

[Explanation of symbols]

11, 11a, 11b, 11c Chip-shaped electronic component 12 Circuit board 13 Component body 14, 15, 14a, 15a, 14b, 15b, 14
c, 15c Terminal electrode 16,17 Electrical connection land 18,19 Mechanical fixing land 20,21,25-35 Mechanical fixing metal surface 22,23,24 Solder

Claims (4)

[Claims] 1. A component main body having a chip shape defined by a lengthwise dimension, a widthwise dimension and a thicknesswise dimension, and having no substantial difference between the widthwise dimension and the thicknesswise dimension, and the component body. In a chip-shaped electronic component, comprising two terminal electrodes formed at both ends opposite to each other in the longitudinal direction, two electrical connection lands to which the two terminal electrodes are soldered respectively; Between the connection lands, the two electrical connection lands are mounted on a circuit board having two mechanical fixing lands arranged in a direction orthogonal to a direction opposite to each other. Either of the two surfaces defined by the longitudinal dimension and the width dimension and the two surfaces defined by the longitudinal dimension and the thickness dimension of the chip-shaped electronic component Even if the substrate is oriented toward the circuit board, a mechanical fixing metal surface located so as to be soldered to the two mechanical fixing lands is formed on the component body. It is a chip-shaped electronic component. 2. The chip-shaped electronic component according to claim 1, wherein the mechanical fixing metal surface is formed so as to integrally extend from the terminal electrode. 3. The chip-shaped electronic component according to claim 1, wherein the metal surface for mechanical fixation is formed independently of the terminal electrode. 4. The two electrical connection lands and the two electrical connection lands are arranged between the electrical connection lands in a direction orthogonal to a direction in which the two electrical connection lands face each other.
A structure in which a chip-shaped electronic component is mounted on a circuit board on which two mechanical fixing lands are formed, respectively, wherein the chip-shaped electronic component is a chip-shaped component main body and a longitudinal direction of the component main body. Two terminal electrodes respectively formed on opposite ends, and a metal surface for mechanical fixation formed on a central portion in the longitudinal direction of the component body, wherein the two terminal electrodes are respectively the two electrical electrodes. A mounting structure for a chip-shaped electronic component, which is soldered to a connection land, and the mechanical fixing metal surface is soldered to the mechanical fixing land.